The site, near Denver, was purpose built so Xcel Energy could just take a before and after meter reading for the entire building. The IT load did not really change over the course of the project, so the reduction was attributed to the shutting off of 39 CRAC units out of 70 units running. This reduction was measured at 435kW, or about 11kW per CRAC unit. These CRAC units were the old AirFlow brand and the per unit reduction was higher than anticipated but we double checked the meter readings and verified the constant IT load (via the UPS) to confirm the numbers.

Old Airflow CRAC Badge

The containment was a combination of cold aisle containment, under floor partitions, and CRAC unit extensions. PUE before was 2.0, after it was 1.8.

Polargy helped calculate the ROI. The project’s net costs were $400K ($569K less $169K). The 435kW savings yielded $225K annually (power rate is about 6 cents per kWh). This results in a project payback period of 1.6 years.